Facsimile scanning and control system



June 17, 1947. A, Q RUSTAU i 2,422,587

j FACSIMILE SCANNING AND CONTROL SYSTEM Filed July 51, 1946 2 Sheets-Sheet l $545070? I: i l 0,7m 507'70/V June 17, 1947. A. c. RUSTAD FACSIMILE scANNING AND CONTROL SYSTEM 2 sheets-smet 2 Filed July 31, 1946 I ARTHUR C'. /usTD 1yr/MMR.

atented .lune 17, 1294? FACSIMILE SCANNING AND CONTRUL SYSTEM Arthur C. Rustad, Floral Park, N. Y., assignor to Press Wireless, Inc., New York, N. Y., a corporation of Delaware Application `luly 31, 1946, Serial No. 687,481

12 Claims.

This invention relates to facsimile scanning machines and more particularly to a continuously operable scanning drum control arrangement for use in such machines.

In certain elds of facsimile use it is often necessary to make a large number of transmissions successively. In such cases when the sheet or film is insucient to accommodate the entire transmission, it is usually necessary to remove the used paper or nlm from the scanning drum before transmission can proceed. 'I'his necessitates keeping the transmission equipment in a state of idleness until a new sheet of paper or film is wrapped on to the drum in place of the used one. An arrangement for overcoming this disadvantage is disclosed in application Serial No. 625,591, filed October 30, 1945.

It is another object of this invention to provide a phasing control circuit arrangement associated with the drive shaft of the scanning drum for starting the drums and providing for continuous scanning after the initial circuit adjustments.

A feature of this invention relates to the plural section scanning drum having successively operable drive controls whereby either section or both sections can be rotated for scanning and with a minimum of required phasing adjustments.

Another feature of this invention relates to the novel phasing and speed control arrangement employing a two-position switch and a novel combination of electron tubes.

A further feature of this invention relates to the novel organization, arrangement and interconnection of parts which cooperate to produce an improved facsimile scanning machine.

Other objects, features and advantages of this invention not particularly set forth will be apparent to those skilled in the art as will be evident in the following descriptions taken in connection with the accompanying drawing, in which:

Fig. 1 is a schematic block diagram of an arrangement employing this invention.

Fig. 2 is a cross-sectional view of the clutch drive arrangement shown in block form in Fig. 1.

Fig. 3 is a schematic diagram showing a mechanical arrangement for effecting operation of the Adesired drum section.

Fig. 4 is a View, partly in circuit diagram form and partly in block form, showing the phasing and speed control features of the invention.

A particular application of the phasing and motor control arrangement of this invention is (Cl. TTS-69.5)

its use in conjunction with the plural drum scanning machine described in application Serial No. 625,591, filed October 30, 1945. Since the scanning drum is described in detail in that application, its description will be conned to that necessary for an understanding of this invention, and parts referred to in this application which are the same in construction and function as corresponding parts referred to in said application Serial No, 625,591, bear the same designation numerals in both applications.

Referring more particularly to Figs. 1 and 2, driven shaft 6 carries scanning drum sections 'l and 8 mounted thereon, shaft 6 -being driven by synchronous motor IIJ through clutch 80. Solenoid 52 is provided to operate clutch 80 in accordance with the setting of selector button switch 51. Drum section 8 is mounted in ball bearing races on shaft '6 and can be stopped Without stopping the shaft 6, or it can be rotated while shaft 6 is stationary. Rotation of drum section 8 without reference to the rotation of shaft 6 is made possible by the provision of resilient but positive drive means between clutch and drum section 8, as represented by the numeral 25. Drum section 'I is pinned to shaft 6 and rotates as a unit therewith. Sections 'I and 8 are of the same diameter and there is a minimum spacing between their adjacent ends in order that the two drum sections can be employed effectively as a single continuous drum surface if desired.

Clutch `8! is driven by worm drive I I (Fig. 2) associated with motor I0. Worm drive II meshes with worm wheel I2, keyed to sleeve I3 which is rotatable with respect to shaft 6. Likewise, clutch plates I4 and I5 are keyed to sleeve I3. Shiftable clutch plates I6 and 22 are slidably keyed on the sleeves I'I and 2I respectively pinned to the shaft 6. Coil springs 20 and 24 cooperating with shiftable plates I6 and 22 respectively normally cause those plates to be held in driving engagement with clutch plates I4 and I5 to cause drum sections 'l and 8 to rotate as a unit. If shiftable plates I6 and 22 are declutched or out of driving engagement with plates I 4 and I5, neither drum section can be rotated by them. If shiftable plate 22 is clutched with clutch plate I5 and slidable plate I5 is declutched from clutch plate I4, the worm II is disconnected from shaft 6 and that shaft and drum section 'I pinned thereto do not rotate but drum section 8 is rotated through the medium of the clutch plate I5, driving plate 22, which in turn causes rotation of the resilient positive drive means 25 coupled to section 8. Conversely, if slidable plate 22 is declutched from plate l5 and slidable plate I6 is clutched with plate I4, the driving or rotation of shaft 6 and drum section 'l pinned thereto is effected while the driving engagement of section 8 is lost.

From the foregoing description, it is readily seen that the relationship of clutch I4 and l5 with the slidable lclutch plates It and 22, determines whether rotation of motor l will effect rotation of neither drum section, both drum sections, or only one of the drum sections. Selector switch loutton is set to control the desired rotation of the drum sections 1 and 8, and the subsequent operation of solenoid 52 causes the solenoid plunger 53 to effect the desired actual mechanical positioning of the elements of the clutch 8G, whereupon motor lil causes the rotation of drum sections 'l and 8 in accordance with the selector switch setting. The actual mechanical arrangement required to effect this operation is described in detail in the above referred to tion and 1sY inY schematic form in ARete ing to 3., shiftable clutch members man L 2g are provided with suitable bnurcated clu h vlevers `-ZQWand 28 respectively lpivotally rnc 281,vk 2,9, containsuappropriate pins 3l and 32 which ed at 6:5 on plate 39". Each hifurcated lever rideuifntheperipherl grooved tace of the associated shiftable clutch memben The lower ends Swf levers 23. and engage arms 33 and 34 fastened to. rocker shafts 55,VV and 36 respectively. siiitabiejccntact rollers ai and as at the end of arm's'fl andSll Yre'spectively are held in contact "the lower ends Bigbyle'af springs 4I and 40 res ective'l'y.` UAMeinlbers 4,3 and 42 attached to rockerfarm's. 5`r'andv 3.5 respectively also carry the"roller'sl'4` .'l. anddl for the purposes to be described. ."Ifhe members '4.3 and 42 also carry the membre 11,4, and' ce weicher@ so @enea bethey are adapted -to latch themselves unvhftlieI nyagnfztv controlled'bar 48. Bar 48 p rted at its ends by rollers 4.9 and 50 in roll`erg des 5f! and 52a respectively which are rigidly ,astenedto the casting which houses solenoid 52..` VVVMembersV 54; andy 55 attached to bar 48 engagez' the"g`rooved portion o f. plunger 513 as SllWfl Y lSelector hutten 5l, normally held in a raised positionfab platernbyspring 58, has a shank 59"whieh`fe rlesfthesemifcircular flat shoe Gil. Shoef'"isfrotatable abouty the vertical axis of shanlgli and`,'i's"arr.anged to depress either, both, or neither oi the rollers 44,6. and 41', thereby efiecting the desired selectionrfor rotation of drum sections Tandil. To eiect the desired selection, pin el? 'or 'button 5,1 is rotated. until it is aligned with ltheholfefin plate 30 which corresponds to that1 sel"V on, andfthen button Slis depressed.

If, it "isf des'red'to have neither drum section rotatewhenthe motor rotates, pin 5I is aligned with hlelfand depressedtherein. Shoe 6,0 then overlie's'both rollers 46 and 41. and both latches. 44 andv 4,5 Aare. depressed andV latch themselves beneath bar 4'8Qjas shown in the dotted position. In thisjfposition, arms 33 and34are rotated in# wardlyV causing.'leversvr 39 to berotated against the forceof Vsprings 20.4v and 24 (Fig. 2)y about their, respevtivel pi v otf5,' thereby declutching shaftt Birjoln the motorv andpreventing both the drum` sections from'iloei'nglrotated.k In this .cori-4 diti n` the'lmor sheet to be scannedis loaded on 'to thedrums. Loading may be accomplished by wrapping.. aj'single, sheet or film around both drumsto forni' ineffecta single continuous scanning drum, or each drum may be wrapped separately to form two scanning drums. When the drums are loaded and the lm or sheet secured thereon and the scanning head (not shown) correctly positioned and the necessary electrical adjustments made, the machine is in condition to begin operation.

Operation is started upon receipt of the start ing pulse by solenoid 52 which causes plunger 53 to move upward causing [bar 48 to unlock the latches 4,4 and 45 allowing slidable clutch memhers Hi and 22 to engage or clutch with clutch plates I4 and I5 respectively. As previously stated, the rotation of either drum section may be stopped by appropriately rotating and depressing button 57 to cause the pin 6l to engage the desired hole in plate 3U. For example, if button 5l is depressed so as to cause shoe 60 to overlie only the roller 41, only the latch 45 latches bar 48. This causes a rocking only of shaft 136 and results in a declutching of s hitable member i6 from Clutch met@ I4. Causing Shat 6 and drum section 1 to' be' stationary while engagement of clutch members l5 and 22 allows rotation of drum section 8, to continue.

Referring to Fig. ll, clutch BilI is shown ina side elevational view taken alo-ngthe line 4-4 of 2.V Commutator ring 8| of suitable insulating material" is aixed around and rotatable with clutch plate-'l5 rlhis commutator includes a short conducting: segment 52, which cooperates withk a carbon brush 83. xedly mounted with respect tothecommntator but contacting with the periphery thereof- The conducting segment S72 is imbedded in ring 8l. and contacts with brush 83,. during each revolution. of the commutator, segment 82 being of such a length that itoccupies approximately. 1,8`o of the commutator periphery,

rIyhe Vmotor; '8.0. is supplied with, amplied current generated by'.` turning fork oscillator 8,4. Whichl'operates, for, example at 2400 C. P. S. This frequency is then subdivided in.y asuitable fr e quency subdivider of any well-known type, e. g., rnultirvibrator 85, to convert the 240010.31 S. into a` 453g. C. E.` S. signal-, which isv then` applied to a keyer, stage whichkeys the 48o C. P. S,

signalonandfoi as willbe described. The keyedfrequencylisfthen further subdivided by multi;-

vibrator 8lv to (i0 C. P. S. which is ampliiledvinV ampliiien 8 8.

The 0n. and. Qfff leerme. of.y stas@ 8.3.-is0n1mol1ed1 bathe Gamed@ resisten 8.9, of: a eridfoetrolled high mu triode S0, wh .acontrcl grid receives a recurrent D, C, phasing; impulse.. from4 the. out.-

nn;V er. the'@munten-renneri; which duringy the.

elimineren@ in the wellyknown a value that.

finer- Rssister 8,9.fis o: such an. increase of, plate. current through tiibe'g.- nvdldbr lthereceived phasing imullle. the dr across, resistor 89; applied: to cathode V925k `of; tube. $3, biases the latterE tubev to plate current. cutoi.Y `When tube 93,isI thus out off, no driving signal is applied to the multi,- vibrator`A 8J, whicntherefpre generates its normal signalfrom. tube S35 is` annue@ to multifvibrator 815th@ lattel'idsliyersa607C, E Si signal.; Thus. the Speed. tsrnhreews motor. le. @mbe conM tlQlled--betWgGH-? arid-602C. B- Sv Itfwillbcclcar therefore, that they received' rectifiedv phasing signal` cannot causecutoffe, oftube 93 so long, as the,.refsistor 829 l' fee-@ive feleiiedlpheseimeulse. ausesfthe. mo.- torz luto lower. itsf speed, Associatedwith com- 1l lied-from.thetransmtter92;

rt-circufitedY Consequently, as long s resistance ,8.29 .isnot short.-circuited` the,y

mutator 8l and tube 90 isN a two-position stayput switch' 94,` and a push-button'switch 95, which is normally in the position shown. When switch 94 is in position #1, resistor 89 is normally short-circuited through the contact 96 of switch 95. On the other hand, when switch 95 is depressed, and assuming brush 83 is riding on the insulated portion of the commutator 8l, the receipt of a phasing impulse' from the transmitter draws sufficient plate current through resistor 89 to cause tube 93 to go to cutoff and causing the motor I to slow down. However, when the motor reaches a speed and phase at which the segment 82 contacts brush 83 coincidentally with the receipt of the phasing impulse from amplifier 9|, this received phasing impulse is ineffective to cause cutoff bias on tube 93, and the motor I9 therefore continues to run at its normal speed of 60 C. P. S. under control of the tuning fork oscillator 84.

After the motor I9 and the drum shaft 8 have thus been properly phased with the transmitter, switch 94 is moved to position #2 and either of the drum sections can be started or stopped under control of solenoid 52 and the selector button 5l as above described. In order to effect starting of a particular drum section, the button 51 is turned so as to engage the shoe 50 with the proper roller 46 or 41 and the push-button 95 is operated. Thereupon, current flows from the positive terminal 91 of the D. C. power supply through the limiting resistor 98 and thence through the winding of solenoid 52 through switch 94 in position #2, through the arm and contact 99 of switch 95, brush 83 and segment 82 of commutator 8l to ground. AS a result of the operation of solenoid 52, the selected one or both of the latch members 44 and 45 is operated under control of the bar 48 so as to operate the corresponding clutch member l 6 or 22. In other words, the segment 82 not only serves the purpose of controlling the phasing but it also controls the application of the starting impulse to the clutch control solenoid 52. Thus, by means of pushbutton 51 and switch 95, either or both of the drums may be selectively started and stopped, it being understood that during the actual operation of the drums for facsimile recording, the phasing signal is not transmitted since the phasing operation is effected preliminarily to the actual transmission and reception of the picture signals.

Thus, if the left-hand drum section 8 (Fig. 1)

is in operation for actual scanning, the righthand drum section 'l may be stationary for loading with another picture. When the loading of section l is completed, the push-button 95 can be operated and the button 51 turned so as to start the drum section 'l in scanning operation. 'I'he scanning head 68 which is operated by lead screw 86 is then allowed to progress towards the right until the right-hand drum section 1 is being scanned. During thescanning of the section 1, the left-hand drum section 8 may be stopped and reloaded and restarted in phase. No additional pulses are required nor is any time consumed between the drum loadings to effect the phasing.

While there has been here described a preferred embodiment, it is understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a facsimile scanning system, scanning drum means divided into separate scanning drum sections, means to drive said sections synchro-v nously as a unit, means including a shiftable clutch having a rotatable clutch member for selectively stopping one drum section without stopping the other drum section, a phasing commusaid commutator, a resistance for developing a motor control voltage in response to a received phasing impulse, and means including said segment and brush for short-circuiting said resistance in synchronism with the receipt of said phasing impulses.

2. In a facsimile scanning system, scanning drum means divided into a plurality of separate drum sections, a common drive shaft for said sections, clutches between said drive shaft and each of said sections, a phasing commutator driven'in synchronism with said drive shaft, an electric motor for driving said shaft, a grid-controlled tube for controlling the frequency of the alternating current applied to said motor, another grid-controlled tube having a cathode load resistor, said other grid-controlled tube adapted to have its plate current controlled by received phasing impulses, a circuit connection for biasing said iirst tube to plate-current-cutoif in response to phasing voltages developed across said cathode load resistor, and means including said commutator for short-circuiting said cathode load resistor during a portion of each revolution of said drive shaft.

3. A facsimile scanning system comprising, a scanning drum, an electric motor for driving said drum, a grid-controlled tube whose plate current controls the speed-of said motor, means for normally biasing said grid-controlled tube to platecurrent-cutoff when said motor is running at the desired speed, another grid-controlled tube whose plate current is controlled by received phasing signals, connections between the said tubes so that the first tube is biased to plate-current-cutoff when phasing signals are applied to the grid of the second tube, and a commutator rotatable with said scanning drum for rendering the second tube ineffective to apply plate-current-cutoff bias to the first tube so long as the motor is driving said drum at synchronous speed.

4. A facsimile scanning system comprising, a scanning drum, a motor for driving said drum, a phasing commutator rotatable with said drum, said commutator having a phasing segment, a source of fixed frequency alternating current, a frequency converter for said fixed frequency, a grid-controlled tube for controlling the frequency converter to deliver to the motor an alternating v current of different frequency from said fixed frequency, another grid-controlled tube for controlling the plate-current-cutoff bias of the first tube, means to apply received phasing signals to the control grid of said other tube, and means controlled jointly by said phasing signals and said commutator for selectively determining the application of plate-current-cutoif bias to said first tube.

5. A facsimile scanning system according to claim 4 in which said frequency converter delivers a lower frequencyto said motor when said first tube is biased to plate-current-cutoff as compared with the frequency delivered to the motor when the said first tube is plate current conductive.

6. A phasing and speed control arrangement for facsimilemachines and the like comprising, an electric driving motor, a tuning fork oscillator, a first multivibrator controlled by said oscillator, a second multivibrator, said iirst multivibrator being connected to the control grid of said tube and said second multivibrator being connected to the plate of said tube, the output of said second multi vibrator determining the speed of said motor, means effective when said motor is operating at synchronous speed for biasing said tube to pass plate current and thereby causing said second multivibrator to generate the normal synchronous frequency for said motor, and means responsive to received phasing impulses for biasing said tube to plate-current-cutoif and thereby causing said second multivibrator to supply a different frequency to said motor.

'7. A system according to claim 6 in which said phasing signals are ineffective to cause said second multivibrator to apply said different frequency until the scanning drum is phased with the said received phasing impulses.

8. A system according to claim 6 in which the said means responsive to the received phasing impulses for controlling the cutoi bias on said tube comprises another grid-controlled tube and a commutator rotating in unison with said scanning drum.

9. A phasing and speed control arrangement according to claim 6 in which the means responsive to the received phasing impulses for controlling the plate conductivity of said grid-controlled tube comprises a second grid-controlled tube whose control grid is excited by thereceived phasing impulses, said second tube having a cathode load resistor which is connected to the cathode of the iirst tube and tending to bias the rst tube to plate-current-cutoff as phasing impulses are received, and a commutator rotating in unison with the scanning drum for short-circuiting said cathode load resistor to prevent received phasing impulses from changing the motor speed when the scanning drum is in phase with a distant transmitter.

10. A facsimile synchronizing and phasing system comprising, a facsimile receiving drum to be phased with a distant transmitter under control of received phasing impulses, a grid-controlled tube for producing a D. C. biasing voltage in response to the received phasing signals, another grid-controlled tube whose grid is arranged to be biased to plate-current-cutoff under control oi said voltage, a driving motor for said drum, a source of current for saidmotor whose frequency varies between two values in accordance with the plate current on and off condition of said second tube, a commutator rotatable with said drum and having contacts recurrently closed during the drum rotation for short-circuiting said bias voltage away from said second tube, and a manually-operable switch for controlling the said short-circuiting action of said commutator.

1l. A facsimile synchronizing and phasing system according to claim 10 in which said second tube is normally plate current conductive and said source of current normally drives said mol`tor atv a synchronous speed when said drum is in phasel with the transmitter, and means to lower the frequency of said source when said D. C. biasing voltage is produced in response to said' phasing signals.

12. A facsimile synchronizing and phasing system comprising a facsimile receiving drum to be phased with a distant transmitter under control of received phasing impulses, a rst gridcontrolled tube having a load resistor across which a D. C. voltage is developed in response to received phasing impulses, a second grid-controlled tube having its grid arranged to be biased by the voltage developed across said load resistor, a commutator rotatable with said drum, and means responsive to the coaction of the received phasing impulses and said commutator for shortcircuiting said load resistor when said drum is in phase with the transmitter.

ARTHUR C. RUSTAD. 

